Electric connecter plug



June v 29 1926.

F; W. HEWITT ELECTRIC CONNECTER PLUG Filed April 22 192 2 Sheets-Sheet 1lnvenror. Frank W. Hewifl by/w War June 29 1926.

F; w. HEWITT ELECTRIC CQNNECTER PLUG Filed April 22, 1924 2 Sheets-Sheet2 lnvenror. Frank W. HewiTr YMWMjM Patented June 29, 1926 UNITED STATESPATENT OFFICE.

FRANK W. HEWITT, OF ARLINGTON, MASSACHUSETTS, ASSIGNOR- TO SIMPLEX ELEC-TRIC HEATING COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF.

MASSACHUSETTS.

ELECTRIC CONNECTEB PLUG.

Application filed April 22, 1924. serial'ivo. 708,246.

This invention relates to an electric connecter plug such as isconnected to a flexible electric conductor and employed for making aseparable attachment with an electric heating or other device such, forexample, as a flat iron. v

The object of the invention is to provide a substantially all metal plugwhich is thus for all practical purposes non-breakable andindestructible. Connector or attachment plugs of this type are commonlyemployed in connection with flat irons, small electric stoves and otherdevices frequently used by unskilled and careless persons. The presentinvention in the all metal feature presents a plug which can besubjected to "extremely rough handling without impairing its usefulnessor its appearance.

The object of the invention is further to provide such aconnecter plugwhichwill present a pleasing and attractive appearance. This result issecured by a sheet metal enclosing casing which presents a smooth andattractive surface and may be given a finished appearance by nickelplating or otherwise.

The object of the invention is further provide a connecter plugwhichwill act after the manner of a quick bre'ak'switch. This result issecured by combining with the plug an anti-kink helical spring securedto the plug and surrounding the flexible conductor, and a heatinsulating sleeve of a. well known phenolic condensation product orother suitable material surrounding and engaging the spring. This sleevealso ensures a suitable hand-hold or grip which will not become heatedeven if the all metal plug becomes somewhat heated. When the operatordesires to remove the plug from the device to which it is connected, theoperator naturally takes hold of this gripping sleeve to pull the plugaway from the terminals. The spring will thereuponexpand until the pulltransmitted therethrough to the plug is-suflicient to overcome the Ericof the all metal plug including various novel insulating features and a.novel construction of a one-piecemetal wire universal socket member. v

These and other objects and features of the invention will appear morefully from the accompanying description and drawings and will beparticularly pointed out in the claims.

In the drawings:

Fig. 1 is a side elevation of a connecter plug embodying a preferredform of the invention with the upper end of the anti kink spring and thegripping sleeve omitted and with the ends of the terminals of a deviceto which it is to be attached shown in place;

Fig. is a perspective view of the body and bridge cap' members of themetal skeleton frame forming a part of the device with these membersshown ready for assembly;

Fig. 3 isa detail partially in longitudinal cross section showing theportion of the gripping sleeve on the anti-kink spring;

Fig. 4' is a view largely in transverse cross section showing'the entiredevice;

Fig. 5 is a view in perspective of one of the socket members;

Fig. 6 is a view of the main portion 'of the device taken in crosssection transversely to that of Fig. 4;

Fig. 7 is a view in cross section taken on the line 77 of Fig. 4 andlooking toward the bottom of the'plug.

The forni of connection plug illustrated for disclosing a simple andpreferred form of theinvention is one suitable for use on a flexibleelectric connecter extending to a lamp socket or receptacle and forattach- In the construction illustrated the connecterplug includes anexterior continuous sheet metal casing which is preferably finished topresent a smooth, attractive design and nickel plated or otherwisesuitably surfaced. This casing preferably comprises a body 1 and a capThe bOL v telescopes within the cap. as shown in Figs. 4; and 6. and isremovably connected thereto by small lugs 3 struck out from the body andengaging apertures 4 formed in thecap. Thus the body may be connected toand disconnected from the cap in a manner similar i to the ordinary lampsocket... This casing is apertured at the top to receive the con--ductor. For this purpose the cap at .the top is formed with a truncatedcone-like shape terminating in an open cylindrical sleeve 6. The casingis also apertured at the bottom or opposite endto, receive the terminalsof the device to which the plug is to be connected, as will appear fromthe subsequent description of'the frame member.

The terminal receiving sockets and the insulating and connectingfeatures of the connecter plug are all preferably secured to andsupported by a skeleton metal frame mounted within and enclosed by thecasing.

This'frame is preferably made, for convenience of manufacture andassembling, in two sectionsrigidly connected together. These sectionsare shown separated readily for assembly inFig. 2. The lower. sectioncom-- prises the'generally U-shaped body having y the base 7 and theuprights '8 terminating in the lugs 9. The upper sectioncom'pri'ses abridge cap member havingjthe central an-.

nular portion 10 with the laterally extending wings 11. These wings areapertured at 12 to receive the lugs 9, and when the parts of the frameare assembled, the

lugs 9 arebent back over the wings 11 as shown in Fig. 4, thus lockingthe two parts 1 of the frame rigidly together. The entire frame isconnected to the cap member 2 of the casing by lugs 13 struck out fromthe depending wings 14 of the bridge cap and fitting into apertures 15in the cap 2; The base; 7- of the frame "and the lower portions ofthe-uprights 8 fitsnugly the body 1 of the casing, and thus the lowerend of the casing is' closed except for the apertures in the base of theframe. W'hen, therefore, the body 1 of the casing is disconnected fromthe cap 2 of the casing the main portion of the frame and the partssupported thereby are all exposedand readily accessible. 7

The socket members which receive the terminals, such as16, of the deviceto which the plug is to be connected, are of metal and in the preferredform present a onepiece skeleton wire construction. One of these socketmembers is separately illusand 23 to receive the attaching device for yholding the socket member in place.

The uprights 8 of the frame body present re-entrant portions 24,'eachprovided with exterior longitudinal ed e flanges 25 and each providedwith a pan of apertures 26. The socket members and the binding posts aresecured to these re-entrant portions 24 of the frame uprights in such amanner as to insulate the socket members .with their binding posts fromthe frame and fromeach other. For this purpose apertured sheets of mica27 and 28 are laid against the opposite faces of the portion 24. Anapertured backing metal plate 29 is laid against the outer face of themica sheet 27, the :1 er- .tured base plate 30 of the metal bin 'ng Ipost 31 is laid against the inner face of the mica sheet 28, and thesocket member is laid against the'inner face of the base plate 30, andthen all these part are firmly L riveted together .by the .rivets 32passing through the aligned apertures. The reentrant portion 24, is sodesigned as to hold the rivets and all metal thus insulated from theframe well away from the casing 1. Theconstruction is the same at bothsides of the frame. The apertures in the mica sheets are much smallerthan the apertures 26in the frame and lateral shifting is prevented bythe flanges 25 and longitudinal shifting by the portions of the frameabove and below the re-entrant portion 24.

v The base 7 of the frame is provided with large" apertures 33.Apertured mica sheets 34 and 35 are placed above and beneath the base 7and metal eyelets 36 are set up in the apertures of the mica plates andthe base so as to clamp the mica plates and base to-- gether rigidly andleave the metal eyelets completely spaced and insulated from the metalof the base and these metal eyelets are arranged in axial alignment withthe socket members. Consequently when the terminals of the device towhich the plug is to be connected are passed through the eyelets 36and'into the socket members there can be no electrical connectionbetween the terminals and the metal of the frame or casing.

trated are of a universal type enabling any shape, round polygonal orflat, of terminal to make a contact and as thesesocketmembers. areresilient this contact is a firm'and yielding one.

\ Further insulation is provided between the'frame and base by largesheets of mica 37 fitting the interior of the casing and laid in betweenthe frame and the casing.

A. helical wire spring 38 is forced into the cylindrical opening in theportion of the cap of the casing and expands at the bottom toform'engagement therewith. The usual flexible, insulated, two-wireconductor 39 is led down through the interior of the spring and througha central aperture 40 in the bridge cap of the frame, and the wiresspaced and knotted beneath this aperture, and the ends of the wiresconnected The socket members in the form illus- I in the usual manner tothe bindin posts 31. The usual thimble 41 is provided at the top of thespring 38.

A gripping sleeve42, which may be of any suitable design, is hereinshown as somewhat globular and of sufficient size to be readily graspedbythe operator and forced over the spring and preferably engagestherewith about midway of its length. This gripping sleeve should be ofsuitable heat insulating material such as a well known phenoliccondensation product. Consequently if the all metal connecter plug heatsup somewhat this sleeve will remain cool. This sleeve serves";therefore, as a handle for the attachment and removal of the plug.Furthermore, by reason of its engagement with the helical spring, itcauses the attachment plug-to make a quick break or disconnection whenremoved from the device to which it is connected because when theoperator seizes and pulls upon this sleeve the spring is expanded untilthe pull transmitted therethrough to the plug is sufficient to overcomethe friction between the plug and the device to which it is connected,whereupon the plug will he suddenly disconnected and the circuit brokenquickly which is a very desirable feature.

It will thus be seen that all the desired objects stated by theinvention are secured by this connecter plug and that there is therebypresented an extremely attractive, eflicient, simple, non-breakable andindestructible, substantially all metal device.

Having thus described the invention. what is claimed as new, and desiredto be secured by Letters Patent, is:

1. An electric connecter plug'comprising an exterior metal casingapertured at the top to receive an insulated conductor, a pair of metalsocket members within the casing and insulated from the casing and fromeach other and connected to the conductor, and metaleyelets mounted inthe bottom of the plug in alignment with the socket members andinsulated from the casing and from each other.

2. An electric connecter plug comprising an exterior metal casingpresenting a body and a cap telescoping and removably connected, a metalsuporting frame enclosed by the casing and having a U-shaped body and abridge cap, means for securing. the free ends of the frame body to thebridge cap, and a pair of metal socket members within the frame andinsulated from the frame and from each other and held by, the frame outof contact with the casing.

3. An electric connecter plug comprising the construction defined inclaim 2 together with means for securing the frame to the from eachother by an unobstructed air space, an aperture in the upper end of thecasing to permit an electric conductor to be passedtherethrough andconnected to the socket members, and a pair of metal eyelets mounted inthe bottom of the frame in alignment with the socket members and insulated from the frame and from each other and from the casing, wherebythe casing body may readily be removed leaving the remaining parts ofthe plug supported by the frame andaccessible.

5. An electric connecter plug comprising an exterior metal casingapertured at the top to receive an insulated conductor, a pair ofone-piece metal wire skeleton socket members within the casing andinsulated from the casing and from each other and connected totheconductor, and metal eyeone-piece skeleton wire socket member presentingfour generally parallel and straight runs forming a skeleton terminalreceiving socket, the connecting runs of oppositely disposed pairs beingoppositely flared to form the socket mouth, andthe opposite ends ofadjacent runs of each pair being extended longitudinally beyond the runconnecting the other runs of each pair at the. socket head and bent toform attachment recelving eyes.

7. An electric connecter plug comprising a metal supporting framecomprising apertured side bottom and top members, metal socket memberssecured to and insulated by apertured mica sheets from the side framemembers, terminal receiving metal eyelets secured toand insulated byapertured mica sheets from the bottom frame member in alignment with thesocket members, and an insulated flexible electric conductor extendingthrough the aperture of the top member with its wires connectedrespectively to the socket members.

In testimony whereof, I have signed my name to this specification.

FRANK W. HEWITT.

